U.S. Pat. No. 7,592,360 (issued Sep. 22, 2009) discloses Compound (I):
or 4-methylbenzyl (3S, 4R)-3-fluoro-4-[(pyrimidin-2-ylamino) methyl] piperidine-1-carboxylate (referred to in the '360 patent as (3S, 4R)-4-methylbenzyl 3-fluoro-4-[(pyrimidin-2-ylamino)methyl]piperidine-1-carboxylate, and elsewhere as MK-0657 or CERC-301). A potent selective antagonist of N-methyl-D-aspartate receptor subunit 2B (NMDA-GluN2B or NR2B), Compound (I) was initially developed for treatment of Parkinson's disease (Addy et al., J. Clin. Psychopharmacol., 49:856-864 (2009)). A pilot study of Compound (I) in patients with treatment-resistant major depressive disorder (TRMDD) showed antidepressant effects in the 17-item Hamilton Depression Rating Scale (HAM-D17) and Beck Depression Inventory (BDI) (Ibrahim et al., J. Clin. Psychopharmacol., 32(4):551-557 (2012)). Due to the study's small sample size, no definitive conclusions as to Compound (I)'s potential efficacy or safety profile could be drawn from the study's preliminary data.